When you’re a parent, it can be tempting to assume you know everything there is to know about parenting – especially once you’ve got through the twin stresses of birth and breastfeeding. 

But perhaps the main lesson of becoming a mother or a father for the first time is that there’s always something new to learn – not least because every new milestone comes with its own unique challenges.

With that in mind, we sat down, with curiosity, to watch the new Netflix series Babies – a 12-parter that promises to “unlock the miracle of babies’ first year” by following 15 different ones around the world during those first 12 months (because Gwyneth Paltrow doesn’t have a monopoly on our doc viewing).

Here’s what we learned from the first two episodes.

Dads bond with their babies in exactly the same way as mums.

We already know that levels of oxytocin, the so-called ‘love hormone’, rise during pregnancy, birth and breastfeeding – all the body’s way of ensuring a mother ‘bonds’ well with her baby. But Professor Ruth Feldman, of the Interdisciplinary Center Herzliya in Israel, made a breakthrough when she realised that the same surge can take place in men, too.

“When mother and baby touch each other a lot, oxytocin levels rise – which makes you want to touch each other more,” Feldman says. It gives you a sense of reward – the higher the oxytocin level, the more the mother bonds with the infant.” Feldman’s study involved 80 couples and measured oxytocin levels in mums and dads from birth into the first month. The results were “really shocking” – because the levels were identical.

“It was a huge surprise to us,” Feldman says. “We’ve known for over 100 years that mothers get a surge of oxytocin during pregnancy, childbirth and nursing – but we discovered that the more you do with a baby – wash it, feed it and engage in that parental role – the more your oxytocin system will activate. This is amazing. Fatherhood is biological – it’s as deep as motherhood.”

Your brain changes when you become a parent. Forever.

You’ve probably heard (or experienced first hand, ahem) that when a baby cries at night, it’s the mother who usually hears the cry first. Even when the dad gets up to change of comfort the baby, the mother is often the one who’s unable to get back to sleep. Feldman says this is because the surge in oxytocin at birth activates the mother’s amygdala – the part of the brain responsible for emotions and empathy.

“The amygdala makes us vigilant and worry about the infant,” she says. “Once the mother’s amygdala is open, it stays like this forever – no matter how old the child is. But in fathers’ brains, it usually activates about a quarter of what you see in mothers.”

And when there’s no mother? Well, Feldman did a study looking at 48 gay couples who had a child via a surrogate. She videotaped the dads at home, interacting with their baby, and also measured oxytocin levels. She then scanned the fathers’ brains.

“Our results showed that when fathers are the primary caregiver, they have amygdala activation – just like mothers. We had no idea we would find that. Pregnancy, childbirth and nursing activate the mother’s brain, but it’s also activated by caregiving. This shows that it’s a choice to be a parent.”

Dirt really is good for your baby.

We’re all pretty careful about telling our children to wash their hands but we shouldn’t worry too much about dirt. That’s according to Professor Susan Lynch, of the University of California who found that babies living with dogs and cats (or even mice and cockroaches) are better protected from developing asthma and allergies.

“In homes with no pets, there’s less bacterial exposure,” Lynch says in the second episode. “Babies raised in those households have a greater chance of developing asthma in childhood.

Conversely, in homes where dogs are present – and to a lesser extent, cats – there’s a much broader diversity of bacteria that the baby is exposed to, and those babies are actually protected from developing asthma.”      

Babies launches on Netflix on 21 February. Check out our weekly series Birth Diaries on HuffPost Parents for readers’ honest accounts of labour and birth.